Grinding-mill.



L WALKER. GRINDING MILL. APPLICATION FILED NOV'. 11, 1909.' RENEWED MAR.26, 1914.

. 1,114,320, Patented o@t.20,1914.

2 SHEETS-SHEET 1.

J. WALKER.

- GRINDING MILL. APPLIoATIoN FILED Nov. 11, 1909. RBNBWBD MAR. 2e, 1914.

1 1 4, 320. Patented 0ct. 20, 1914.

2 SHEETS-SHEET 2.

dz Walker,

UNrrnD s'rA'rEs vrarnN'r OFFICE.

JOHN WALKER, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO JOIIlSll WALKERMIACHINE` COMPANY, F BOSTON, MASSACHUSETTS, la CORPORATION OFMASSACHUSETTS,

GRINDING-MILL Speccation of Letters Patent.

Patented oct. 2o, r1914.

Application led November 11, 1909, Serial No. 527,375. Renewed March 26,1914. Serial No. 827,486.

To all whom it may concern:

Be ity known that I, JOHN WALKER, 'of

Boston, inthe county of Suffolk and State of Massachusetts, haveinvented certain new and useful Improvements in Grinding- Mills,lofwhich the following is a specification. v

This `invention relates to. grinding mills and particularly to machinesof this general character which are particularly adaptedtogrindchocolate-or other substance when prepared in a semi-fluidcondition.

The principal object of the invention is to provide `a mill which isadapted for automatically grinding the material over and over again `asmany times as the nature of the substance may require.

A further object is to provide means for heating the mill and forcausing a circulating fluid to flow through the rotating grindingcylinderthereof for either cooling or heating the same.

A construction of mill by which the above objects may be carried intoeffect andV in which the forni of the invention at present preferred byme is embodied, is shown in the accompanying drawings, in which- Figure1 is a vertical longitudinal section of the grinding mill. Fig. 2 is asectional plan view of the base portion of the mill on line 2*2 of Fig.l. Fig. 3 is a vertical cross-section on line 3 3 `of Fig. l. Fig. L isa detail sectional view on a large scale of the grinding cylindersshowing the dress with which the same is provided. Fig. 5 is a partialelevationv of the surface of the cylinder showing one form of dress.Fig. 6 is a view similar to Fig. 5 showing another form of dress. y

The same characters indicate the same I parts in all the figures.

rlhe essential parts of the mill consist of a trough or concave a, agrinding cylinder b, a conduit 0r gutter c and an `inlet d from theconduit to the interior of the concave. The latter is preferablycylindrical in form, being approximately a semi-cylinder- It has acylindrioally-curved inner -surface which surrounds the lower portion ofthe grinding cylinder and plane end members a which embrace the lowerparts of the cylinder ends. .The conduit or gutter c sur rounds theconcave and cylinder and is of greater depth on one side thereof than onthe other. The inlet d extends from the deepest part of the conduit intothe interior may fall into the shallower part of thecon duit. Thematerial runs thence past the ends of the cylinder into thedeepest partof the conduit and thence back through'the inlet a? for re,:,'rinding.The conduit thus provides for. a circulation of the material by'whichafter it is ground it may be con-- duct-ed back to the starting pointand be reground repeatedly as many times as desired until, when theparticles are sufficiently fine,`

`it may be drawn off through an outlet f.

This outlet extends from the vdeepest part of the conduit and isnormally closed by a Agate g which can be openedwhen'the material is tobe drawn o The details of construction of the mill are preferably suchas are illustrated. lThe-conduit is formed in the upper part of a castVmetal base h and entirely surrounds a central opening c' in said base.AThe outer rim of the conduit is vsupported by the Walls of the base andits inner portion is supported by a number of webs j, which extend fromthe walls of the base nearly'to the corners lof the opening or recess i.

The concave or semi-cylindrical trough a is set into the opening z' andis provided with a peripheral lip a2 which rest-s on the inner rim ofthe conduit. At its inlet end the concave has flanges a3, which aresecured to flanges c of the conduit by such means as the bolts c2.' Theinner Wall of the conduit is open where attachment is made with thenipple a3 in order that the material may flow into the inlet d.

The outlet f previously referred to is-a tube extending from the bottomof the conduit at its lowest point out through the adjacent wall of thebase. The gate g is a plate which is detachably secured over the end ofthe outlet by any convenient means such as a bolt or bolts g.

As shown in Figs. 4, 5 and 6 the periphery of the cylinder is providedwith a dress which may be either inclined as shown in Fig. 5, orstraight across the face thereof as shown in Fig. 6. The dress is formedby parallel grooves,'each `of which prefer` ably has one wall abrupt andthe other wall formed on a general slant. There is also a grindingaction between the end walls of the concave and cylinder, which wallsmay be also dressed in a. similar manner, if desired. The material ofwhich the cylinder and concave are made may be either metal, as steel orcast iron, or stone, if preferred.

A hood Z extends over the upper part of the cylinder to preventspattering.

A heating coil m is contained within the base below-the concave for thepurpose of maintaining the temperature of the latter and of the materialbeing ground up to the desired point. There is also provided a means foiflowing circulating fluid through the cylinder for either preventing thelatter from becoming over-heated or maintaining it at a certaintemperature. For this purpose a shaft a of the cylinder is provided withpassages o and p extending from opposite ends as far as the interior ofthe cylinder,'whicli is made hollow. The passage 0 has an outlet i" fromwhich a tube s extends out to the peripheral wall of the cylinder and aninlet t permits the overflow to pass out Y through the passage p. Anyform of coniiection usual for such purposes may be made between the endsof the shaft and pipes for the circulating fluid. I,

I claim:

l. A grinding mill, comprising a grinding cylinder arranged with itsaxis horizontal, a concave surrounding substantially the lower half ofthe cylinder, a conduit surrounding the open mouth of the concave,extending on a downward slant from the side at which the cylinderemerges from the concave to the side at which it enters, and an inletleading into the concave from the lower side of the conduit, foreffecting a gravity feed of material once ground back for regrinding.

2. A grinding mill, comprising a grinding cylinder arranged with itsaxis horizontal, a concave surrounding substantially the lower half ofthe cylinder, a conduit surrounding the open mouth of the concave, ex-

,of gradually increasing depth extending around said cylinder andconcave, from one side thereof to the other. Y

4. A grinding mill comprising a grinding cylinder, a concave embracingthe bottom and ends of said cylinder, a conduit of gradually increasingdepth extending around said cylinder and conca-ve from one side `thereofto the other, and an inlet from the deepest part of said conduit to theinterior of said concave.

A grinding mill comprising a grinding cylinder, a concave embracing thebottoni and ends of said cylinder, a conduit of gradually increasingdepth arranged to receive the ground material expelled from the concave,and extending around said cylinder and concave from one side thereof tothe other, and an outlet from the deepest part of said conduit fordischarge of the ground material.

6. A grinding mill comprising a coperating rotary cylinder and concave,a scraper located to act on the upwardly traveling side of said cylinderabove the concave, and a conduit intov which the material issuing frombetween the cylinder and concave and removed from the cylinder by saidscraper falls, extending downwardly to the lower portion of the concaveand having an admission inlet thereto.

'i'. A grinding mill adapted to accomplish :successive grindings of thesaine material,

comprising a grinding cylinder and a concave, which constitutecooperating grinding elements, said cylinder being surrounded only atits lower portion by said concave,

side of the concave at which the ground material is expelled therefromon a gradual incline to said inlet.

8. In a grinding mill, a concave open at the top and having an inlet ata lower point, and a conduit surrounding said concave and communicatingwith said inlet, said conduit having its greatest depth at the saidinlet.

9. A grinding mill havi'ng a grinding coupley consisting of a cylinderand a concave, provisions for feeding material to be ground into saidconcave, the concave having its upper termination below the top of thecylinders, -means for removing material adhering to the cylinder as thelatter emerges from the concave, and means for conducting the materialso removed to the inlet of the concave.

In testimony whereof I have aflixed my signature, in presence of twowitnesses.

JOHN WALKER.

Witnesses C.' F. BROWN, P. W. PEzzE'r'rI.

